Integrated Hohlraum Simulations of Double Shell Implosions with the 2-Shock Laser Pulse*

We present integrated Hohlraum simulations of Double Shell capsule implosions [1,2] using the 2-shock laser pulse. Double Shell implosions explore volumetric ignition at the National Ignition Facility. The capsules are composed of a low-Z outer shell and a high-Z inner shell which contains the fuel. The outer shell functions as the ablator. After being accelerated inwards by the Hohlraum drive, it collides with the inner shell and transfers its energy and momentum to it. The inner shell then compresses the fuel to ignition conditions. For our simulations, we use the LANL multi-physics code xRAGE [3,4] with its new capability to model capsule implosions in integrated simulations that include the Hohlraum. Here, we focus on the 2-shock laser pulse which is a candidate to reduce the imprint of the ablator joint gap. The latter is a result of the outer shell being assembled from two hemispheres which are connected at the equator. If the corresponding joint is not fully closed, i.e. contains a gap with a large width, it can have detrimental effects on capsule performance. We discuss the outcomes of our xRAGE Hohlraum studies, sensitivities of simulation outcomes to physics and numerical settings, as well as comparisons to the LLNL Hydra code. 

 

[1] D. S. Montgomery et al., Phys. Plasmas 25 (2018)

[2] E. C. Merritt et al., Phys. Plasmas 26 (2019)

[3] M. Gittings et al. Comput. Sci. Disc. 1.1, 015005 (2008)

[4] B. M. Haines et al. Phys. Plasmas 29, 083901 (2022)